Worksite preparation typically includes grading and excavating portions of the worksite to form desired finished topologies and footprints. Positional measuring is a critical element in most construction and agricultural worksite applications and the use of laser receivers to facilitate positional measurements in such applications is widespread. For example, laser receivers are commonly attached to construction equipment (e.g., dozers, scrapers, excavators, and the like) to improve grading and excavating accuracy.
With respect to laser detection, these laser receivers typically include multiple radiation or sensing arrays, which are spatially arranged in a vertical pattern and which respond to impingement by a radiation source such as a laser beam. To achieve high precision and 360 degree detection such lasers typically utilize three (3) or four (4) sensing arrays spaced at 120 degree or 90 degree intervals, as the case may be. Each array of the laser receiver includes multiple individual photo detectors and associated monitoring circuitry.
One established laser measuring technique and measuring system utilizes a projection of a laser beam by a rotary irradiation (e.g., a laser transmitter) for the purpose of forming a horizontal reference plane or a reference plane tilted with respect to the horizontal reference plane at a predetermined angle and by which it is possible to measure a position by using the transmitted laser beam. In this way, the applicable measuring instruments measure the coordinates of a point by sending a laser beam to the point. The laser beam may impinge directly on the point or may impinge on a retro reflector target that is contact with the point. The measuring instruments determine the coordinates of the point by measuring the distance and two angles to the target. For example, in U.S. Pat. No. 7,196,302 to F. Ohtomo et al. (hereinafter “Ohtomo”), U.S. Pat. No. 7,966,739 to F. Kamizono et al. (hereinafter “Kamizono”), and U.S. Pat. No. 8,788,154 to R. M. O'Connor et al. (hereinafter “O'Connor”) laser surveying and laser measuring systems are described that utilize N-beams in combination with certain photo detection techniques to measure positional data. However, while the aforementioned systems provide highly accurate results, the ability to utilize multiple, independent laser receivers to simultaneously calculate positions remains a challenge.
Therefore, a need exists for a three dimensional (3D) measuring system that allows for the use of multiple, independent laser receivers to simultaneously calculate positions without any need to communicate with the laser transmitter.